1. Field of the Invention
The present invention relates to an ac generator's stator for a passenger car or a truck and a method of manufacturing the same.
2. Description of the Related Art
An insulating structure between a stator core and a stator winding of an ac generator's stator for a vehicle is disclosed in JP-A-8-80001, in which insulation film sheets are disposed between slot walls and the stator winding. Each slot has an opening formed at the inner periphery of the stator core, which is closed by a separate press-fitted wedge member to retain in-slot portions of the stator winding inside the slot.
Because the insulation film member and the press-fitted insulation member are separate in such a stator core, small gaps are necessarily formed between the two members. When a rotor rotates inside the stator, pressure near the slot openings rises. As a result, snow mixed with salt or salt water may be introduced into the slots through the small gaps by the cooling air blowing on the stator winding. This causes electrolyzation of the in-slot portions of the stator winding thereby resulting in insulation failure of the stator winding.
On the other hand, the space factor of the in-slot portions of the stator winding has been increased to satisfy recent demand for increasing output power of the vehicle ac generator. The separate wedge member has become an obstacle to increasing in the space factor.